Machine vision is as an important development requirement to advance the state-of-the-art of industrial robots. In addition, machine vision will have a profound effect on the concepts and methodology of the approaches now taken for on-line quality control monitoring or automated inspection.
Until recently, machine vision systems have consisted primarily of an optical receiver or camera, a transmitter or lighting system, "hard optics" to couple the target image to the receiver, and a computer video image analyzer to digitize and process the picture element, or pixel, information received from the camera interface. However, based upon the development of image transmission via fiber optics, the concept of the fixed based machine vision system may now be expanded to include the capabilities of fiber optics.
The propagation of light in optical fibers is based upon geometric and waveguide theories that have been developed over the past decade to well established principles. When a large number of regularly packed fibers are optically isolated from each other, each fiber can convey an element of an image that is formed on one end of the bundle to the other end of the bundle. A basic requirement of this image transfer is that each fiber end of the bundle have some well defined geometric relationship to its opposite end, that is, spatial coherence, in order for the image to be transferred intact via the optical fibers. This technique is called imaging via spatially coherent fiber optics.
The number of applications for quality control monitoring using fiber optic imaging is so diverse and encompassing that the following list is presented only to indicate the possibilities available using this mode of inspection:
1. Dimensional inspection of small parts, i.e., bolts, screws, wire diameter, etc. PA0 2. Parts placement inspection, i.e., missing parts, displaced parts, incorrect parts, etc. PA0 3. Dimensional gaging of large parts--automotive, machine tool, large equipment, etc. PA0 4. Height measurement requirements--food industry for fill levels of cans, cereal, etc. and pharmaceutical industry for pill level in bottles, etc. PA0 5. Gaging dimensional limits--textiles, web and thread dimensions; pharmaceuticals--bottle cap seal detection; machine tool--die protection. PA0 6. Grading and sorting based upon dimension and placement of parts.